I Didn't Know That: Water Rockets

RICHARD AMBROSE (PTC): If you wanted to travel into space you need the backing of a government and a rich government at that. But it's all starting to change. The 21st century is heralding the arrival of the rocketeer privateer

VO: On the 21st of June 2004 SpaceShipOne went rocketing into the history books when it became the first privately funded manned vehicle to make it into space. It was carried to an altitude of nearly 14 kilometers by its launcher White Knight before it broke free and fired its own rocket engine. Although it only burned for 80 seconds the rocket produced enough thrust to send the tiny craft hurtling one hundred kilometers above the Earth, to come down the wings were tilted and SpaceShipOne flew effortlessly to Earth.

JONNY (SYNC - TO RICHARD): Oh right - I thought he was the guy the made the pickle. Anyway how much have we got?

RICHARD: 30 quid. 30 quid. But with some creative thinking I think we can come up with something.

JONNY: Yeah - yeah - cool.

RICHARD: Yeah.

RICHARD AMBROSE (PTC): So Jonny and I have come up with a pressurized water rocket. You can make these at home. What you need is an air pump that supplies the pressure. You need a bicycle valve, from an inner tube. A section of wine cork, screwed in there like that. That's the clever bit. A bit of water. A stand. And obviously the rocket which is my mini V2.

VO: Getting the ratio of water to air right is crucial. Richard reckons a two liter bottle, filled with a third of water, should launch it to a good height. When the cork can't withstand the air pressure any more, you have lift off.